Superman vs. Shazam! #1

Immortal Martian wizard Karmang plans to bring Superman's and Captain Marvel's Earths together in a giant cataclysm to produce enough energy to release his fellow Martians from their ghostly existence and end his torment for putting them in that state. With the help of Black Adam and the Quarrmer, Karmang sets Superman against Captain Marvel to keep the heroes distracted while he executes his plot. But with the help of Supergirl and Mary Marvel, Superman and Captain Marvel stop Karmang's plans and save both Earths.